The mechanical arthropod vectorStomoxys calcitransinfluences the outcome of lumpy skin disease virus infection in cattle

Abstract

The poxvirus lumpy skin disease virus (LSDV) is the etiological agent of lumpy skin disease (LSD), a severe disease of cattle and water buffalo that is characterised by numerous necrotic cutaneous nodules. LSD is a rapidly emerging disease, spreading into and across the Middle East, eastern Europe, and Asia in the past decade. The disease causes substantial production and economic losses in rural communities and affected regions. LSDV is mechanically transmitted by haematophagous arthropods including stable flies (Stomoxys calcitrans), however our understanding of this mechanical transmission method is sparse. A secreted saliva collection methodology using a modified artificial membrane feeding system was optimised for S. calcitrans and used to collect and characterise secreted S. calcitrans saliva. Saliva was mixed with LSDV and shown not to affect virus growth in primary bovine fibroblasts. S. calcitrans saliva or spot-feeding by S. calcitrans was then incorporated into a bovine in vivo experimental model of LSD to determine if either influenced disease pathogenesis. S. calcitrans saliva resulted in fewer animals developing disease, however this difference was not statistically significant. Spot-feeding with S. calcitrans prior to inoculation did not alter the number of animals that developed disease or the overall severity of disease however disease progression was accelerated as demonstrated by the appearance of cutaneous nodules, detection of viral DNA in the blood stream, and production of neutralising antibodies. This shows that S. calcitrans influence disease kinetics through co-incident bite trauma and/or saliva deposition. This increases our understanding of LSDV pathogenesis and highlights the overlooked importance of mechanical vectors in pathogen transmission.

Molecular Detection of Lumpy Skin Disease Virus in Naturally Infected Cattle and Buffaloes: Unveiling the Role of Tick Vectors in Disease Spread

“…The isolation of the virus from ticks proved the potential role of ticks in the transmission of LSDV, and this result agrees with (Tuppurainen et al 2013). It is not surprising to detect and isolate LSDV from ticks, which agrees with previous studies that veri ed the survival of LSDV in ticks even in the absence of disease symptoms, and ticks that feed on skin lesions of viremic cattle were found to be positive (Cook et al 2023). The detection of LSDV in tick larvae highlights the potential of larvae as a source of infection for susceptible animals.…”

“…isolated from skin biopsy, blood, and ticks' samples using unique primers for P32, VP32, G protein, and viral fusion protein genes. Lane M: marker with molecular weight marker (3000 bp); Lane 5 and 12 positive results at 412 bpLane 1, 2, 3,4, 6,7,9,11,12,13,14, and 15 positives at 192 bp Lane 1C-: negative control; Lane 5C+: positive control for LSDV. Figure5(c).…”